An Egypt-backed cease-fire between Israel and Hamas fell apart Tuesday as rocket attacks from Gaza were again answered by Israeli airstrikes .

The rocket attacks from Hamas militants in Gaza never ceased , Israeli officials said . For its part , Israel refrained from airstrikes for about six hours before announcing it was resuming them .

A CNN crew witnessed at least five Israeli strikes just as the announcement was made .

`` Hamas closed the diplomatic option . We woke up this morning in the hope there 'd be a cease-fire and , as you reported , Israel restrained from all our activities , all action against terrorists in Gaza for a full six hours . We gave this cease-fire our full support , '' Mark Regev , spokesman for Prime Minister Benjamin Netanyahu told CNN 's `` The Situation Room with Wolf Blitzer . ''

`` But Hamas said no to everyone . Hamas said no to the cease-fire , both in word and in deed , '' Regev said .

The faltering of the cease-fire attempt means there may be little hope of seeing an end to the near constant exchange of fire that has so far killed more than 190 Palestinians in Gaza .

The first fatality on the Israeli side was a man killed Monday after being hit by a mortar shell , Israeli Rescue Services said . He was an Israeli volunteer who was at the Erez border crossing to deliver food to soldiers .

Israeli leaders had agreed to the cease-fire , but from the outset warned it would be short-lived if the attacks from Gaza did n't stop .

The Israeli Security Cabinet met early Tuesday morning and decided to halt aerial strikes beginning at 9 a.m. -LRB- 2 a.m. ET -RRB- . It resumed strikes about six hours later , by 3 p.m. -LRB- 8 a.m. ET -RRB- .

Gaza crisis : Who 's who in Hamas

The barrage from Gaza continued , with more than 140 rockets fired from there since early Tuesday -- or one rocket every six minutes -- according to the IDF .

`` Hamas have decided to continue , and will pay the price for that decision , '' Netanyahu said Tuesday .

His Security Cabinet met again late in the day for emergency talks .

The Egyptian plan calls for all sides to cease hostilities in Gaza . It also calls for the opening of border crossings , once the security situation is stable , and for high-level talks among those involved .

`` The achievement of the success of this Egyptian effort is a must for all of us , '' said Palestinian negotiator Saeb Erakat . `` It 's an interest for all of us , and if we allow things to deteriorate I think it 's going to be a disaster all over . ''

He continued : `` Failure is not an option here . ''

When the plan was announced , there was a split reaction from Hamas . Its military wing rejected any possibility of a cease-fire , while its political wing had said it was considering it .

Ismail Haneyya , deputy chairman of Hamas ' political wing , said at the outset of the Egyptian efforts that there is a bigger issue than a cease-fire for Palestinians .

He said that what Palestinians really want is an end to the Israeli blockade on Gaza that is suffocating the daily lives of the 1.8 million Palestinians living there .

Haneyya , speaking on Hamas-owned Al Aqsa TV , also accused Israel of not freeing Palestinian prisoners from Israeli jails , as had been agreed to under an earlier truce . These , he said , are elements the Palestinians would like to see in a comprehensive cease-fire agreement .

Hamas spokesman Osama Hamdan later stressed that Hamas never received the proposal through political channels .

`` We are still working with Egypt . We are still talking to other sides , '' he told CNN .

`` I believe a proposal is supposed to be prepared after the sides agree on it . It 's supposed to be published if two sides give agreement on it . You ca n't publish it in the media and then ask everyone to accept that or reject that . ''

Asked why Hamas wo n't stop firing rockets while talks are ongoing , the spokesman replied : `` We are not the side who is killing the other side . We are are the side being killed . ''

Trapped in war : ` This is tyranny '

Civilian casualties

The stakes are high and climbing .

By Tuesday , the death toll from a week of Israeli airstrikes on Gaza had reached 194 , with at least 1,400 wounded , according to Palestinian health authorities .

The toll is now greater than the number of people killed in Gaza during the 2012 conflict between Israel and Hamas .

The United Nations has said that most of the people killed by Israel 's aerial attacks are civilians .

`` I urgently call on the Israeli Security Forces to put an end to attacks against , or endangering , civilians and civilian infrastructure which are contrary to international humanitarian law , '' said Pierre Krahenbuhl , commissioner general of the United Nations Relief and Works Agency for Palestine Refugees , or UNRWA .

There are now 17,000 refugees taking shelter in 20 schools in Gaza , UNRWA said , and the airstrikes have damaged 47 of its buildings , including clinics , schools and warehouses .

The Israeli military says it uses a variety of methods , including phone calls and leaflets , to warn civilians of impending strikes .

`` As part of our effort to avoid harming civilians , we are sending messages to residents of northern Gaza to leave homes for their own safety , '' the IDF posted to Twitter late Tuesday .

But UNRWA called on Israel to exercise maximum restraint and precautions to avoid more casualties .

`` Clearly , at this stage not enough is being done in that regard , '' Krahenbuhl said .

Israel Defense Forces spokesman Lt. Col. Peter Lerner accused Hamas of holding the people of Gaza hostage .

`` They are using and abusing the houses , the infrastructure there , in order to carry out these attacks . We really do n't have any other choice , '' he said .

Hamas on Tuesday closed a crossing between Gaza and Israel but allowed 25 Palestinians -- some of them needing medical attention -- to cross into Israel at Erez .

The border crossing at Erez was closed not as punitive measure , but because the Gazan side has been targeted in airstrikes , said Maher Abu Subha , the head of the committee for border crossings in Gaza .

Employees at the crossing have been targeted three times in three days , and it was closed out of fear for the lives of the workers , he said .

The crossing can be reopened quickly if Israel can guarantee the workers ' safety , he said .

Kerry delays trip

U.S. Secretary of State John Kerry was preparing a possible trip to the Middle East to lay groundwork for a cease-fire , but he postponed the visit to give Egyptian efforts a chance to take root .

One official said the United States wants to give Egypt a chance to reassert itself as a power broker in the Middle East , as it did during the 2012 cease-fire .

Kerry continued to follow that line Tuesday .

`` The Egyptian proposal for a cease-fire and negotiations provides an opportunity to end the violence and restore calm , '' Kerry said from Vienna , Austria . `` We welcome the Israeli Cabinet 's decision to accept it . We urge all other parties to accept the proposal . ''

Kerry strongly condemned the rocket launches by Hamas in the face of the cease-fire plan , and said he is prepared to fly to the Middle East as early as Wednesday , if needed .

The current Egyptian President , the ex-military chief Abdel Fattah el-Sisi , has weaker relations with Hamas than former President Mohamed Morsy , who brokered the 2012 deal . Morsy was ousted by the military in 2013 .

Palestinian Authority President Mahmoud Abbas will travel to Egypt on Wednesday to meet with the President and to discuss a possible cease-fire , the official Palestinian news agency WAFA reported . Abbas also is scheduled to visit Turkey .

Earlier , Kerry spoke by phone with Netanyahu and expressed U.S. concerns about escalating tensions . He reiterated that the United States is prepared to help bring about a cease-fire , a senior State Department official said .

But `` offering facilitation is not enough , '' Yousef Munayyer of the Washington-based Palestine Center told CNN 's `` New Day . ''

`` It 's important that the United States demand a cease-fire , '' he said . `` There is no military solution to this . ''

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`` Hamas closed the diplomatic option , '' says spokesman for the Israeli PM

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A spokesman for the military accuses Hamas of holding the people of Gaza hostage

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`` We are not the side who is killing ... We are the side being killed , '' says Hamas spokesman

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The Gaza death toll is higher than the number of people killed there during the 2012 war